New type of four stroke engine

[GyroRon]

Just bought a new toy-tool for work. These just came out, the dealer got it's first shipment in today. It is a blower with a fourstroke engine but it uses two stroke mixed gas ( 50 to 1 oil to gas ratio )

there is no oil to change, no oil filters and the thing is light. 20 pounds or so for the whole unit. I am not 100 percent sure the size of the engine, but I think it is around 60cc. Power is something like 5 horsepower.... whatever it is, the dam thing blows harder than any other backpack blower I have used.

Downside is you do have to adjust the valves every once in a while, but that shouldn't be too hard.


Some of the other manufactors have tried fourstroke engines for weedwackers but they all used a oil sump and didn't really like to run upside down. They are all heavy too. This one is light and powerful and runs upside down just fine. They are making weedwackers with a smaller version of this engine and if I like this blower after using it this season I might go four stroke on the trimmers next year.

[Brent_Brown]

Ron do you have a price on it. I just got this motor today and it is a 49cc with Ele. start, has a clutch and a 5 to 1 gearbox. I won it on e bay for $85+ SH. It is New never started. I hope to get it on my pegleg gyro as a pre rotator somehow.

[GyroRon]

the blower was just under 400$ with tax. That little motor you got looks like one of those china made engines for the scooters and minibikes they are selling at Pep Boys. should do okay

[RickAbercrombie]

Four stroke model aircraft engine, They been doing that for years.

[scottessex]

Details Man! So it's like a big model airplane engine.

[GyroRon]

Yeah I never even thought about it, but it is just like the model engines. The four strokes use the same fuel - well basically the same but slightly different - and just adds a cam lobe to the crankshaft and some push rods and a set of overhead valves. This engine is the same thing except it runs on gas and doesn't smoke and is pretty darn quiet for what it is. If you have ever had much experience with a four stroke model airplane engine, this thing sounds exactly like one from idle to full throttle.

[CLS447]

How is it that it doesn't smoke when it's burning premix?

[Brent_Brown]

Yes it is off one of the scooters. From what I can find it is around 2 HP. I will bring it to BDs so who ever wants to see it feel it they can.

[scottessex]

like this:
http://www.popsci.com/popsci/bown/2003/article/0,18881,537079,00.html

[http://www.stihl.ca/pressOffice_release_revolutionary4mix.asp

[GyroRon]

Chris, try an experiment..... Take a jug of heavily mixed gas - say 25 to 1 ratio - that would smoke like crazy in a two stroke, and put that gas in your four stroke lawnmower, or your car or even gyro and see how much smoke it makes. I have done this a zillion times and I have never seen or even smelled smoke from the four stroke engines.

[Dale Young]

Here Is a Giant Scale Cub that I converted a 30cc JD/Homelite for. pulls like a mule and sounds neat with the pipe. The Picture was taken when we lived in an apartment. The wife LOVED it hangin' out in the dining room for TWO DAYS!!! :rolleyes:

[automan1223]

Wow ron thats great news. I always knew you were looking for a better blow-er.

now all we have to do is scale it up and put on a gyro. wonder how many of those backpacks it would take to get you airborne ! Like a B4M. with stihl all over . wonder what the displacement is.

Jonathan

[C. Beaty]

2-strokes smoke because some of the fresh charge short circuits and goes straight out the exhaust. Oil mist in a hot exhaust manifold is what makes the smoke.

[GyroRon]

Chuck, I notice when my gyro is first started it smokes quite a bit, but after it is fully warmed up and especially after landing from a flight, it appears to blow out little to no smoke at all power settings. Is this cause tolerances are tighter and less blow by is happening? Or something else I am just not thinking of?

[C. Beaty]

After a 2-stroke engine has been sitting for a while, oil drains down into the crankcase and when first started, a slug gets blown straight through to the exhaust ports, making a cloud of blue smoke.

Tuned pipe 2-strokes when on the pipe, don’t smoke as much as say, weed whacker engines. The pressure waves in the pipe ram most of the unburned mixture back into the cylinder.

4-stroke engines burning 2-stroke mix don’t smoke because the oil burns in the same way as gasoline. All the oil does is lower the octane rating.

The 4-stroke leaf blower engines need roller/needle bearing connecting rods just like 2-stroke engines; leakage of oil that condenses on the cylinder walls into the crankcase provides marginal lubrication. Plain connecting rod bearings wouldn’t live very long.

[mceagle]

Ron, just after you land the manifold and pipe are still very hot and burn the oil readily. If you idled long enough for the exhaust to cool down, it would start to smoke again. The smoke is often hard to see because it is readily dispersed into the propeller slip stream.